Flanges Rating

Very Briefly:

The flange rating 150#, 300#, 600# ...indicates the suitability of the flange to work at higher pressure & temperatures i.e. as the design temperatures & pressures increase, you would change from a 150# to 300# to 600# flange. Generally, if you look at ASME B16-5, you would see that 300# flanges are thicker and probably have more bolts / thicker bolts that 150#

Dear Hussain,

#150,#300,#600 stands for the maximum working pressure rating of 150 psi, 300psi and 600psi respectively. normally the details of this you can find in ASME B16.5 FLANGE STANDARD.

NASIM KHAN

Agreed, but it's worth adding that the nominal rating, 150psi, 300psi etc are at elevated temperature ~ 500 - 800°F - varies with the rating, but figures are in the tables. (don't know why these particular temperatures are used, it seems rather arbitrary). So if you're working at lower temperature the pressure can be 2 - 3 x higher than nominal rating, again figures are in the tables.

The metric system, PN6, PN10, PN16 etc works the other way round. 6bar, 10bar, 16bar etc are at ambient temperature, and must be derated at elevated temperature.

Codey

#150,#300,#600, .... etc. is just a rating or class nomination for standard flanges, and doesn't denotes to any max. or min. working pressure or temp. neither respectively nor irrespectively. I mean no relation between rating #150 and pressure 150 psi. From its name, the Pressure Temp. Rating depends on Design Pressure and Design Temp. of a Specified Material. See ASME B16.5, Table 2 for different groups of materials.

Thanks for your answer. it is exactly what I was thinking. My boss keeps giving me the idea that # and psi are equal, i.e. 200psi = 200#. I don't buy it.

It has a relation to the non-shock pressure , # 150 means it will withstand pressure of 150 psig @ 500 degree F , and for # 300, 600 , 900 , 1500 , 2500 it means that the flanges will withstand the pressure of this rating value at temperature of 850 degree F.

Dear All,

How about JIS 10K? according to flange pressure rating ASME 16.5 ie: material ss 304, the flanges rating can withstand up to 18bar which is higher than JIS 16K

What is the different between JIS 10K and 16K exspecially in pressure rating (phsyical dimension might be different)

Please advice

Here is a link that should be pretty close to the temperature/pressure ratings for each flange class. Hope it helps.

http://www.piping-toolbox.com/ansi-flanges-pressure-temperature-d_342.html

"In C.S.Flanges What does Class#150 or #300 stand for if anyone advice me in details"

IIRC 150 and 300 psi, respectively.

CS Flange Ratings

Temperature and pressure service ratings.

This is a "pet peeve " of mine. To elliminate the confusion you may have, as ASME B 16.5 correctly refers to ratings of flanges (pressure/temperature) as CLASS, not pound. That is to say that the terminology of 150 # is archaic and should be stated correctly as Class 150, etc. As you will see in the standard, almost all used metallurgy have material components along with their reference tables for allowable working pressures at required process temperature. Use of a certain material is up to the engineer responsible for understanding corrosion, hardness, etc. needs for material appropriate for the fluid (liquid/gas/vapor).

I hope that this doesn't perturb those with old habits, but right is right.

Pete (Control Systems)

A guy in my office wants to know who and or how they came up calling it 150# and not class 150 etc..

The classes 150#, 300#, ... etc. are "just" considered as a categorization or family name for each group of flanges. The calling up is first created by ANSI under ANSI B16.5 and ANSI B16.47, and starting from 1998 the publications issued under ASME B16.5 and ASME B16.47.

Note. 150# ≡ Class 150 ≡ Rating 150, all three names are correct.

Hi,

I have few issue need your advice:

my system design was 14 bar at temperature 90 deg.C and i'm using flange JIS 10K. According to calculation of flange pressure rating ASME 16.5 i got maximun design pressure approx 18 bar and material i'm using is SS 304.

I need your opinion can i withstand with flange JIS 10K instead of JIS 16K. How about flange gasket? still it take into consideration on determine pressure rating? or any other parameter have to taking care in calculation of design rating?

from the max. design pressure, how much safety margin we should apply? can we hydrotest with max. design pressure x 1.5 ?

Please advice

The actual class rating system is based on the first actual use of the ASME code which is for steam piping and boiler design. The ratings refer to the once actual ratings of the flanges derated for steam ( I can't remember if it was for saturated or a certain degree of superheat). i.e. 150 # flanges are rated for 150# steam. However, over the years as metallurgy has improved and derations have lessened for some materials, this is not entirely accurate.